<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>15.symbol的内置属性</title>
</head>
<body>
<script>
  class Person {
    static [Symbol.hasInstance](params){
        console.log(params)
        console.log('检测函数被调用了！')
    }
  }

  let  o1 = {}

  console.log(o1 instanceof Person)

  let arr1 = [1,2,3]
  let arr2 = [4,5,6]
  arr2[Symbol.isConcatSpreadable] = false
  console.log(arr1.concat(arr2))

</script>
</body>
</html>